CHAPTER 6: USER MAINTENANCE
UB25 LINEAR DC RESISTANCE WELDING CONTROL
6-6
990-665
Electrode Maintenance
When a welding schedule has been suitable for a particular welding application over many welds, but poor
quality welds are now resulting, electrode deterioration could be the problem. If you need to increase
welding current to maintain the same weld heat, the electrode tip has probably increased in surface area
(mushroomed), effectively decreasing weld current density, thus cooling the weld. Try replacing the
electrodes.
The rough surface of a worn electrode tip tends to stick to the work pieces. So, periodic tip resurfacing
(dressing) is required to remove pitting, oxides and welding debris from the electrode. You should limit
cleaning of an electrode on the production line to using a # 600 grit, silicon carbide electrode polishing
disk. If you must clean a badly damaged tip with a file, you must use a polishing disk after filing to ensure
the electrode faces are smooth.
The best method of preventing electrode problems is to regularly re-grind electrode tip surfaces and shapes
in a certified machine shop.
Parts Replacement
There are no replaceable parts for the Power Supply, other than the protection fuse for the 24 Volt Air
Valve Driver.
Fuse
DESCRIPTION
LOCATION
3 A, 125 V, Slow-Blow
Rear Panel
WARNING
•
Only qualified technicians should perform internal adjustments or replace parts.
•
Removal of the unit cover could expose personnel to high voltage.
•
Removal of the unit cover may void the warranty.
